This invention relates to water-reducible phenolic resin binders and, more particularly, to novel water-reducible phenolic resin binders exhibiting improved properties for use in coating systems and methods for preparing such binders.
Phenolic polymer resin binders for use in coating systems are known. U.S. Pat. No. 5,770,750, for example, discloses certain alkyd and aralkyd derivatives of phenolic polyol polymers and their use in coating systems. Such products may be constituted by an ester which is the reaction product of a fatty acid with an aliphatic hydroxyl moiety of an alkoxylated phenolic aralkylation polymer comprising the alkoxylation reaction product of (1) an alkoxylating agent such as an alkylene carbonate with (2) a phenolic aralkylation polymer comprising the reaction product of a phenolic monomer having at least two free reactive positions, a styrene derivative and a coupling agent such as formaldehyde. It is also known to react 1,4-cyclohexanedimethanol and trimellitic anhydride with polyester resins. Further, while trimellitic anhydride has been used in making water-reducible binders, it has been found that it tends to cause hydrolysis of resin ester groups and render the resins water-insoluble.
There is a continuing need to develop improved water-reducible phenolic resin binders which are stable in water, provide early water resistance, good chemical resistance and hardness and which are compatible with other materials and speed drying time when used in coating systems.